jQuery In Place Editor is a plugin for jQuery that makes text on the web page editable in a way similar to the way Flickr does. The editable text is highlighted on mouseover. Clicking the text turns it into a text box or text area for text input. Clicking outside the input text box submits (POST) the changed text to the preset URL.
There are other controls with similar and extended functionality but I like the way this one actually does things in a way very similar to Flickr.